Analysis of the NMR spin-spin relaxation time on healthy and damaged human tissues: a new tool for recognition of physical abuse?

Physical abuse is a modern crucial problem with sociological, juridical, humanitarian and public health consequences being the true incidence of the abuse really unknown (i.e. over 3000000 clinical cases every year only for child abuse are registered). The first basic step is the recognition of physical abuse, and physicians work in team to reject all the other possible causes of those lesions in a multidisciplinary differential diagnosis. For instance, the presence of bruises could be correlated with an abuse and nowadays there is a symbiotic relationship between the dermatological and radiological examinations in the successful detection and diagnosis of inflicted trauma to infants and children. Suspicious skin lesions may request skeletal survey. Radiological referral for a focal indication may suggest visual inspection of the entire body, therefore radiologists play a key role in the early diagnosis and imaging of suspected inflicted injury. In this framework, a crucial point is the dating of injuries, since it helps to reconstruct the trauma’s history and to recognize legal responsibilities. The skin is the most commonly presenting organ in physical abuse, and bruises are the most common signs. However, very little research has been performed on dating such lesions, besides the few existing objective and quantitative studies lack of solidity and reproducibility. 1-3 Among the objective diagnostic techniques, Magnetic Resonance Imaging (MRI) is an excellent candidate being adequately spread and safe for patients. On this basis, we started to use 1H-NMR to study intrinsic characteristic NMR times (responsible of the contrast in MRI) in human tissue samples, taken from corpses according to Police Mortuary Regulation. Our goal is to find the various components of the multiexponential NMR signal decay with a robust and replicable method of data analysis and to identify protons of different molecules, each one having possibly a specific identifiable temporal evolution related to the degree of development of the injury. In this way, one could hope to date the injuries (bruises, hematomas, fractures...) helping the justice. We measured samples of both healthy and bruised human tissue from seven anatomic regions of different corpses with different skin conformation, to see how their various molecular composition influences the analysis. To date we limited our analysis to 0.2 T and 1.41 T magnetic fields, being the widest fields currently used in the clinical practice. The present work hopefully puts the basis for the usage of multiexponential analysis in MRI as a quantitative approach to establish dating and degree of damage for injuries reported in abuses.